This invention relates to effective utilization of a transmission line through band compression of voice signals.
Typically, speech information is generated by human mouth and recognized to have significance only after it has been received and identified by human ear. In actual practice, however, voice containing an enormous amount of redundancy is transmitted. This indicates the existence of excessively much redundant portions not required for the purpose of delivering information. Most of the past studies on band compression technology of voice signals centered on this redundancy.
A prior band compression system has been aimed at reducing either the occupied band of individual voice signals or the occupied time rate. Therefore, at the transmitting terminal, a band compression system is provided for each circuit and its output is multiplexed by a multiplexor. At the receiving terminal the voice channel converter provides signals of individual channels, and then the original voice signals are restored from the band restoring device provided for each circuit. That is, a band compression and a restoration device are required for each circuit--limitations to be accepted if conventional technology is to be relied upon.